Database systems are collections of files stored on computers or linked systems such as the Internet. The files together contain all the information about a topic or related topics. Generally, a file system is used to “file away” information which a user will later retrieve for processing.
Normally, a file resides in directly accessible storage and can be manipulated as a unit by file system operations. A file system allows a user the means for storing data in files, accessing the data in those files, managing direct access to storage space where the files are stored, and guaranteeing the integrity of those files. Businesses, e-businesses, and other organizations use databases to manage information about clients, orders, client accounts, etc.
Many businesses use databases to organize information and provide the ability to manipulate that information in a variety of ways. These databases are increasingly server-based databases, available for use by both employees and clients through the Internet. Large relational databases are used by companies to manage, for example, information about clients, orders, client accounts, etc and by e-businesses to sell products or access to specialized information over the Internet.
To minimize the network transmission overhead time, the SQL workload performed against the database server should be server-based. These server-based workloads is primarily comprised of invocations of stored procedures and user-defined functions, written either entirely in SQL or in a fully-capable programming language such as C language, COBOL language, or Java®. When such routines are executed, they must perform in a fault-tolerant manner. This ensures that failures of the programs do not affect other database workloads or the execution of subsequent routines; essential availability of the database to clients or employees must not be compromised.
The current popularity of the Java programming language has naturally led to it being used to code database stored procedures and user-defined functions. The client, user, or employee accessing the database writes a user-defined function in Java to access and manipulate the data in the database through the network. This program may access the data many times which is time consuming for the user and resource consuming for the database. If there exist many users accessing the data in the database, the user-defined function may cause contentions against the data in the database.
For a database management system (“DBMS”), to execute such a Java or other non-native language routine, there must be available to the DBMS a Virtual Machine runtime in which to execute this routine. An attribute of such routines is that many types of failures cause the Virtual Machine, to terminate. When the virtual machine terminates, it usually requires the process in which it is running to also terminate in order to start another virtual machine instance; the virtual machine leaves threads and other hooks in the process that must be cleared and initialized.
Some database implementations are designed to allow the virtual machine runtime to execute in a database engine process. Consequently, when the virtual machine terminates, the database engine must be shut down and restarted, causing the database to be unavailable to clients or employees while the database is down. These database outages are costly to the e-business and annoying to clients. Other database implementations have this virtual machine running in an external process. When the virtual machine terminates, a new virtual machine process must be started, causing other implementations of non-native language routines to wait, introducing a possible failure mechanism for those virtual machine processes while they wait.
Thus, there is a need for a robust, fail-safe environment that, upon failure of non-native language routine program, allows the DBMS to execute a new non-native language routine procedure by another user without requiring the DBMS or operating system to shut down and start over. The need for such a system has heretofore remained unsatisfied.